Gear-cutting machine



W. C. FARNUM.

GEAR CUTTING MACHINE.

APPLICATION FILED JULY 22, I918.

1,373,956. Patented Apr. 5, 1921. Q

4 SHEETSSHEET 1.

iawwa'wa a W. C. FARNUM.

GEAR CUTTING MACHINE.

APPLICATION FILED JULY 2211918.

Patented Apr. 5, 1921.

4 SHEETS-SHEET 2-.

lnwenifor: #M a y fw m.

fliiarngg W. C. FARNUM.

GEA'R CUTTING MACHINE.

APPLICATION FILED JULY 22.1918.

Patented Apr. 5, 1921.

4 SHEETS-SHEET 3.

Invenior W. C. FARNUM.

GEAR CUTTING MACHINE.

APPLICATION FILED JULY 22.19rs.

Patented Apr. 5, 1921.

4 SHEETS-SHEET 4. E

Inn/r:

WILLIAM C. FARNUM, OF WINCHENDON, MASSACHUSETTS.

GEAR-CUTTING MACHINE.

Specification of Letters Patent.

Application filed'July 22, 1918. Serial No. 245,983.

This invention relates to the art of making gears, and among other objects, 'provides a simple machine whereby gears having curved teeth may be quickly produced at a small cost.

The present application is a continuation in part of my copending a plication Serial No.'167,178 filed May 8, 191%.

In the usual method employed for making curved tooth gears, it is customary to cut one Working face or profile of each tooth progressively around the blank, and then the blank is readjusted with reference to the cutter and the opposite working faces of the teeth are cut. The progressive cutting of the opposite faces of the teeth in this man ner, and the re-adjustment of the blank, require considerable time, and there is always a possibility that in making the adjustment, the cuts, on the opposite faces ,of the teeth will not be the same, and accurate symmetrical teeth will not be produced. One of the objects of the invention is to provide a cutter whereby the opposed working faces or profiles of a tooth may be simultaneously cut in one operation, thereby enabling the teeth to be out in less time than is required in cutting the teeth by the former'method referred to.

In the usual method employed for making intermeshing gears having curved teeth, it is customary to out similar teeth on both gears, so thatone gear is a replicaof the other. Another object of the invention is the production of intermeshing gears, one of which is formed with teeth, each having opposed working faces curved on parallel lines cutting the pitch circle, and each space between adjacent teeth having opposed working facescurved on non-parallel lines cutting the pitch circle; and the other gear having spaces, each provided with working faces curved on parallel lines cuttingthe pitch circle, and the opposed working faces of each tooth being curved on non-parallel lines cutting the pitch circle. The construction is such that the parallel profiles of a tooth of one gear fit the parallel profiles of the space between adjacent teeth of the other gear, and the non-parallel profiles of a tooth of the second gear fit the non-parallel profiles of a space between adjacent teeth of the first gear. Thus, the teeth of one gear accurately fit the spaces of the other gear and the inter-engagement of the teeth is as- Patented Apr. 5, 1921. v

sured throughout the lengths of the teeth,

and the full strength of the teeth is available for exerting thetransmission pressure.

The usual machines used for making gears having curved teeth employ highly organized complex mechanisms for supporting the cutter and blank and relatively moving the.

sameto cut a tooth in the blank, to separate the blank and cutter upon completion of a tooth, and to index the blank to bring the .same progessively into-positions for making successive teeth on the blank. Another object of the invention is to provide simple and effective mechanism for relatively positioning the blank and cutter for the production of curved teeth on the blank, and simple and elfective mechanism for indexing the blank between the operations of cutting successive teeth.

The character of the invention may be best understood from the following description of one good form thereof shown in the accompanying drawings, wherein Figure 1 is a view partly in end elevation and partly in section of the machine;

Fig. 2 is a vertical section taken on line 22-ofFig.3;

Fig. 3 is a plan of the machine; Fig. 4 is a horizontal sectional detail taken on line 4 4 of Fig. 1;

Fig. 5 is a horizontal section'showin'g one of the cutters and the means for driving the same;

Fig. 6 is'a horizontal section through the double annular toothed cutter showingthe relation of the same with a gear b'lank'insimultaneously cutting the'opp'osed working faces of a tooth'of one of the gears;

Fig. 7 is a horizontal section through the single annular toothed cutter showing the relation of the same with a gear blank-in simultaneously cutting the opposed working faces of a tooth space for receiving a I tooth of the other gear;

Fig. 8 is a front elevation of the cutter and blank shown in Fig. 6;

Fig. 9 is a front elevation of the cutter and blank shown in Fig. 7

Fig. 10 on an enlarged scale, shows portions of intermeshing, dissimilar gears produced by said cutters, the teeth of said gears being shown in sections taken on the pitch circles of the gears; and

Figs. 11, 12 and 13 show different positions of the gear blank as it is rolled across the double annular toothed cutter to generate an involute tooth.

Referring to the drawings The standard 1 is formed at the upper end thereof to present bearings in which is journaled a horizontal spindle 3 adapted to be driven at various speedsby stepped pulleys 5.

A suitable'cutter is provided for simultaneously forming the opposed working faces of a tooth of one of the gears. In the present instance of the invention, a rotary cutter 7 (Figs. 6 and 8) is provided for this purpose, which comprises a head 9 adapted to be threaded on a reduced end 11 of said spindle. One of the cutters, in the present instance of the invention, is in the form of a ring 13 fitted and secured in a recess in the head 9, and having teeth 15 projecting outward from said head and disposed in an-' nular arrangement. Each tooth may be tapered toward its outer end, and may present a forward active cutting end 17 (Fig. 8), and taper rearward toward a substantially narrower end 19 to allow clearance in making a cut. The cutter described will serve to produce of a tooth.

The other cutter comprises a series of teeth 21 disposed in annular arrangement outward somewhat from the teeth 15, and set in recesses 23 in said head. To permit the teeth 21 to be adjusted so as to project the same distance from said head as the teeth 15, their inner ends may engage screws 25 threaded into said head. Thus, if the teeth 15 are reduced in sharpening same from time to time, the teeth 21 may be adjusted and set accordingly. The teeth 21 will serve to form the working face or profile opposite the face produced by the teeth 15.

A suitable cutter 27 (Figs. 7 and 9) is provided for simultaneously cutting theopposed working faces of a space suitable for receiving the tooth formed by the cutter described. In the present instance of the invention, this cutter comprises a head 29 threaded on the reduced end 11 of the spindle, and provided with teeth 31 disposed in annular arrangement. Each of these teeth one working face or profile has a wide forward end 33.and tapers rearward to a substantially narrower end 35 to allow clearance cuttin j Either the tooth forming cutter or the tooth space forming cutter may be mounted the blank in proper relation to the cutter.

To accomplish this, in the present instance of the invention, a bracket 37 (Figs. Land 2) is mounted on the front face of the standard 1 referred to, and is guided by a dove-tailed projection 39 on said standard (Fig. 4) adapted to be received by a similarly shaped groove 41in said bracket. To adjust the bracket vertically, a screw 43 may be provided having its lower end seated in a socket 45 (Fig. 2), said screw being con-, fined against vertical movement by a collar 47 fast thereon confined between a circumferential shoulder of said socket, and a cap. 49 secured by screws to said socket, said screws also serving to secure the socket to the base of the standard. The screw 45 is threaded to a sleeve 51 entered through a bore in the bottom of the bracket and secured by a flange 53 and a nut 55 engaging opposite faces of the bottom of said bracket. To rotate the screw, it is provided with a hand wheel 57 fast thereon at a point immediately above the socket. struction described, the operator may grasp the hand wheel and rotate the screw, thereby moved in a direction parallel to the axis of the spindle for a purpose to be described.

To support the blank on the table, the latter is provided with uprights 71 having a bridge bar 7 3pivoted to one of said uprights and adapted to be locked to the other by a swing bolt 75. 1 i

A mandrel 77 is vertically disposed be tween the uprights 71 and has conical ends supported in conical bearings in an upper plug 79 threaded in said bridge bar 73 and in a lower plug 81 threaded in said table. The upper plug may be adjusted to take up wear and secure the mandrel accurately in By the con- Y shaped guideway 69 to allow the table to be Y position without lost motion. Lock nuts 83 on the plug 79 secure it in its different positions of adjustment.

A sleeve 85 is mounted on said spindle and has a foot 87 adapted to rest against the upper end of a boss bearing 89 rislng somewhat.

above said table. The mandrel 77 preferably rotates with the sleeve 85 as the tapered sockets in which the ends of this mandrel are mounted permit the mandrel to rotate freely therein.

The gear blank 91 (Fig. 2) is mounted on the sleeve 85 and is supported in the appropriate vertical position to be acted upon by the cutter, by a spacing washer 93 interposed between the foot of the sleeve and the lower end of the blank. To index the blank and hold the latter in different positions of rotativeadjustment, a master gear 95 ma be mounted on the sleeve 85 and be spaced rom the gear blank by a washer 97 on said sleeve. To secure the blank and master gear to the sleeve, a nut 99 is threaded on said sleeve adjacent the top thereof, and engages the upper end of a washer 101 interposed between said nut and the master gear. The construction is such that when the nut 99 is adjusted toward the foot of the sleeve, it will confine the blank, the master gear, and the spacing washers between them, and relative rotation of the blank and master gear will be prevented. The supporting sleeve therefore, however, may rotate on the end thrust bearing 89. r

The bridge bar. 73 may be readily unlocked and rocked upward to facilitate mounting of the gear blank and master gear on the sleeve, and the removal of the same therefrom. Washers of different sizes may be used on the sleeve properly to position thereon gear blanks of difierent sizes as required.

Coiiperatin with the master gear 95 is a worm 103 igs. 2 and 3) on a shaft 105 journaled in bearings in a plate 107 secured to the top of the standard.

This worm may be locked against rotation, or may be manually rotated, or may be automatically rotated as desired. 7

To look said worm against rotation, one end of its shaft projects outwardly and has a disk 109 (Fig. 1) .fast thereon provided with peripheral locking notches adapted to receive a dog 111 pivoted on a pin 113 secured to said plate 107. This dog may cooperate with the notched disk to lock the worm against rotation, or it maybe thrown out of engagement with said disk to permit rotation of said worm.

To facilitate manual rotation of the wor shaft, a hub 115 is mounted on the outer end thereof adjacent said disk, and provided with suitable handles 117.

To automatically rotate said worm, a spiral gear 119 (Fig. 3) is mounted fast on the shaft for said worm adjacent the lock disk and meshes with a spiral gear 121 (Fig. 1) fast on the end of a horizontal shaft 123 journaled in bearings in the standard. This shaft is rotated by a pinion 125 fast thereon, meshing with an idler gear 127 driven by a gear 129 fast on the spindle 3 referred to. The gear 125 may be splined to the shaft 123 and be secured in positions in and out of engagement with the idler 127, by a screw 125 threaded in the hub of said gear.

To generate involute teeth on the blank, the latter is rolled across its cutter, and the master gear is rolled along the worm, which may be locked against rotatiton and serve as amok in this method of cutting the teeth.

To automatically reciprocate the bed 59 to produce the rolling action referred to, the bed may be provided wit-h an arm 131 (Figs. 1, 2, and 3) projecting laterally therefrom, slotted to form a guideway 133 receiving a block 135 adapted to be held in different positions of adjustment in said guideway by a screw bolt 137. This block is connected by a link 139 to the upper end of a rocking arm 141 fulcrumed on a pin 143 secured to an ear 145 projecting laterally from the lower end of the knee referred to. A roller 147 is mounted on a pin 149 secured to said rocking arm adjacent the upper end thereof, and is adapted to work in a cam groove 151 in a cylinder 153 secured on one end of the horizontal shaft 155 journaled in bearings in the knee beneath the top thereof. A worm gear 157 fast on the opposite end of said shaft meshes with a worm 159 beneath it fast on a horizontal stud shaft 161 journaled in a bearing in a bracket 163 secured to the knee. This stud shaft is connected by a universaljoint 165 (.Fig. 3) with one end of a telescoping shaft 167, the opposite end of which is connected by a universal joint 169 with a stud shaft 171 journaled in a bearing in the standard. A gear 173 fast on said stud shaft meshes with an idler gear 175 driven by the gear 129 referred to on the spindle 3.

By the construction described, the cam will be automatically driven from the spindle in the various positions .of vertical adjustment of the knee, and the cam will cause the bed to be reciprocated transversely to the axis of the spindle, thereby in the direction of the arrow b.

cutter so that the blank may be indexed by engagement of the master gear with an indexing dog to be described. To explain the manner in which a ,tooth is generated, attention is called to Figs. 11, 12, and 13. In Fig. 11, the relation of the blank to the double cutter, is shown at the commencementof the cut. It will be understood that the cutter is rotating about the axis of the spindle, and that the blank is receiving a movement oftranslation in the direction of the arrow (1, and at the same time is rotated Consequently; as the blank progresses to the posi tion shown in Fig. 12, the outer annular toothed cutterente'rs the blank and commences to generate one of the working faces of the tooth. As the blank moves to its position, shown in Fig. 13, the outer and inner annular toothed cutters complete the generation of the opposed involute working faces of the tooth. This simple operation results in the completion of one tooth on the blank. Itis unnecessary to first make the roughing cut and then a finishing cut to form the tooth, but the latter is quickly and completely formed by this simple operation. 1

Next will be described means for automatically indexing the blank in readiness for the generation of the next tooth thereon. To accomplish this, a dog 177 (Fig. 3) is pivoted on a pin 179 mounted on an arm 181 projecting outward from the standard.

The dog has a heel 183 normally held against the side of the standard by a leaf spring 185 secured to said standard. The dog is located in the same horizontal plane as the master gear. The construction is such that when the bed moves to the right in Fig. 2, it rolls the blank out of engagement with the cutter and rolls the master gear from its position shown in full lines in Fig. 3 ofi of the wormtoitsposition shown in dotted lines in said figure. In the course of this movement the master gear is engaged by the dog and rotated an increment equal to the pitch of the teeth. When the bed is moved back toward the left in Fig. 2, the master ear will roll back into engagement with t e worm, and the blank will be brought opposite the cutter in readiness for the generation of the next tooth in a. manner similar to that described for the first tooth.

Preferably the bed is given a more rapid movement to the right for indexing the blank than the movement to the left for generating .a tooth in order to economize time. In order to accomplish this, the cam is formed with a sharper pitch for moving the bed to the right than'the pitch for movin the bed to the left.

Turing the generation of a tooth, the

table on which the blank and master gear are supported, is maintained a fixed distance from the worm and cutter. To adjust the table to the position desired, a horizontal screw 187 is threaded into said table and rotatively mounted in a bearing in an upstanding flange 189 on said bed. The screw is confined against axial movement relatively to said bed by a collar 191 and a hand wheel 193 engaging opposite sides of a flange. By rotating this hand wheel the table may be readily adjusted toward and from the worm and cutter as desired.

To determine the depth of the cut to be made in the blank by the cutter, the table may be adjusted inward until limited by the intermeshing engagement of the master gear and worm. The plate 107 carrying the worm 103 will, of course, need to be adjusted when the *table, master gear and blank are adjusted to vary the depth of tooth cut. This may be accomplished by providing screws 107 entered through elongated slots 107 in the plate 107, as will be noted'in Fig. 3. When the table is given this adjustment, the tooth is completely generated in one traverse of the bed to the left of Fig. 2, but obviously a part, such, for example, as one-half the depth of a tooth might be cut in one traverse and completed. in another traverse after further inward adjustment of the table, master gear and worm. In case a second traverse is used to complete the cutting of the teeth, the plate 107 should be adjusted prior to each traverse so that the worm 103 and master gear 95 will properly mesh.

It will be understood that the bed is continuously reciprocated to generate teeth and progressively index the blank until all of the teeth are generated throughout the cir- 'cumference of the blank. Then the gear thus formed is removed from the, mandrel and its sleeve, and a fresh blank is substituted therefor. Teeth may be formed on this blank by the double annular toothed cutter in the manner described, or if desired, the single annular toothed cutter may be substituted for the double annular toothed cutter, and spaces may be formed in the blank appropriate to receive the teeth formed on the previous blank.

In some cases it may be desirable to manually adjust or index the blank. Thls may be readily accomplished by moving the mdexing dog 177 out of range from the master gear, and rotating the worm by means of the handles 117 on the worm shaft, wh le the worm 103 is in mesh with the master gear. a

In some cases a gear blank may have a different pitch circle diameter from themaster gear. The worm may be automatically rotated to impart a rotative movement to the gear blank to compensate for this difference in diameter. To accomplish this, the lock dog 111 is rocked out of engagement with the lock disk 109 and the gear 125 is slid axially of its shaft to bring the same into engagement with the idler 127. This will cause the worm to be automatically driven forthis purpose. stood, of course, that gears of appropriate sizes must be used in the train between the spindle 3 and the shaft 123, in order to impart the correct degree of rotation to the gear blank to compensate for the diameter difference referred to.

In Fig. 10 is shown on an enlarged scale, sectional portions of dissimilar mating gears made by the machine described. tions of these gears are taken on the pitch circles thereof. The gear 195 has teeth 197, each having a convex working face 199 parallel to a concave working face 201 along lines traversing the pitch circle. The concave face of one tooth, however, is not parallel to the convex face of the next adjacent tooth.

The gear 203 mating with the gear 195 has spaces 205 for receiving the teeth of the gear 195, each space having a concave working face 207 parallel to a convex working face 209. The convex face, however, of one space is not parallel to the concave face of the next adjacent space. Thus, although the gears are dissimilar, the teeth of one will accurately mesh with the spaces of the other and contact of the working faces throughout their lengths will be effective in transmitting rotation from one gear to the other.

The cam may be formed to feed the blank relatively to the cutter at different speeds orat a varying speed in the course of the tooth cutting operation according to the amount of work on the cutter. Also, the cam may be formed to vary the speed of the return movement of the cutter.

It will be understood that the invention is not limited to the machine described, but that various deviations may be made therefrom, without departing from the spirit and scope of the appended claims.

Claims:

1. A machine for cutting teeth of gears, comprising, in combination, a toothed cutter for cuttingteeth on a gear lolanlg means to rotate said cutter, a mandrel supporting said gear blank, a master gear'on said mandrel, a worm meshing with said master gear adapted to serve as a rack toroll the gear blank across the teeth of the cutter, and means for rolling the master gear and gear blank out of engagement with the worm and cutter respectively to allow indexing of the gear blan 2. machine for cutting teeth of gears,

It will be under- The seccomprising, in combination, a toothed cutter for cutting teeth on a gear blank, means to rotate said cutter, a table, a frame on said table, a mandrel supported by said frame, a master ear, means to hold said master gear and lank on said mandrel, a worm meshing with the master gear adapted to serve as, a rack to roll the gear blank across the teeth of the cutter, and means for moving said table to roll the master gear out of engagement with the worm to allow indexing of the gear blank.

3. A machine for cutting teeth of, gears comprising, in combination, a toothed cutter for forming teeth on a gear blank, means to rotate said cutter, a table, a frame on said table having a removable bar, a mandrel held between said table and bar, a master gear, a worm, means to hold said master gear and blank on said mandrel in position to be engaged by said worm and cutter respectively, and bearing elements upon said bar and table for adjustably supporting said mandrel.

LA machinefor cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a table, a frame on said table'having a movable bridge bar, a

mandrel held between said table and bar,

a master gear, means to hold said gear and blank on said mandrel, and a worm meshing with said gear.

5. A machine for cutting teeth of gears comprising, in combination, .cutter means for forming teeth on a gear blank, means to rotate said cutter means, relatively adjustable bearing elements, an upright member interposed between and rotatably supported by said elements, an indexing gear, and means to secure said blank and gear on sald member.

6. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, means to support said gear blank, a master gear, an 1ndexing dog fixed against movement bodily, and means to move said gear toward and from said dog to index the blank.

7. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a gear element, an indexing dog, an indexing gear meshing w1th said element, a support for said gear and gear blank, and means for moving said support to shift said gear from said element to said dog to indexthe gear blank, said do comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a gear element, a master gear to mesh with said gear element, means to roll said blank away from said cutter means and said master gear away from said gear element, and means for automatically'indexing said blank after it is free from'said cutter means.

9. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means 1 to rotate said cutter means, an indexing gear, a gear elementadapted to mesh therewith, means to roll said blank and indexing gear away from said cutter means and gear element, respectively, and means cooperating with said indexing gear for automatically indexing said blank and gear after they are 'free from said cutter means and gear elements. 7

' 10. A rmachine for cutting teeth of gears comprising, in combination, cutter means for forming teeth'on a gear blank, means to rotate said cutter means, an indexing gear, a gear element adapted to mesh therewith, means to roll said gear along said element 7 to generate a tooth, and means operating through said element to additionally rotate said indexing gear to compensate for any difference between the pitch circle diameter of said indexing geariand blank.

12. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a worm, an indexing gear adapted to mesh with said worm, and means to automatically rotate said worm to turn said indexing gear to compensate for any difierence between the pitch circle diameters of said indexing gear and blank. 7

13. A machine for cutting teeth of gears comprising, in combination, cutter' means for forming teeth on a gear blank, means to rotate said' cutter meansIa worm, an indexing gear adapted to mesh with said worm, gear means for automatically rotating said worm to turn said indexing gear to coinpensate for'jany diiference between the pitch circle diameters of said indexing gear and blank. y

14. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, and indexing gear, a support for said blank and gear, a worm, and means to rotate said worm to 1ndex the blank or to compensate for any difference between the pitch? circle diameters of said indexing gear and blank,

15. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cuttermeans, a worm, an indexing gear forsaid blank adapted to mesh with said worm, a wheel connected to said worm, and a dog for locking said wheel against rotation. r

16; A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a worm, an index-' ing gear for'said blank adapted to mesh with said worm, and means for rotating said wormeor locking the same against rotation at will.

17-. A machine for cutting teeth of gears, comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a worm, an index-.

ing gear for said blank adapted to mesh with said worm, a support for said gear and blank, and means including acam for moving saidsupport to roll said gear along said worm to generate a tooth.

;18. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, a spindle for rotating said cutter means, a gear member, an indexing gear for said blank adapted to mesh with said member, a support for said gear and blank, cam and follower means for reciprocating said support to roll said gear along said member to generate the teeth, and means to drive said cam from said spindle.

19..A machine for cutting teeth of gears comprising, in combination, a standard, cutter means thereon for forming teeth on a gear blank, driving means on said standard, a gear member, an indexing gear for said blank adapted to mesh with said member, a support for said gear blank, a knee adjustably connected to said standard, cam means on said knee for reciprocating saidsupport,

and transmission means between said driving means and cam means for rotating the latter when said knee is indifferent positlons of adjustment.

. 20. A machine for cutting teeth of gears comprising, in combination, a'standard, a 1 knee adjustably connected thereto, cutter.

means on said standard for formingiteeth on the gear blank, a rotatable gear member on said standard, an indexing gear for said blank mounted on said knee and adapted to mesh with said gear member, driving means on said standard, and transmission means between said driving means and said knee for moving said indexing gear relatively to said-gear member.

21. A machine for cutting teeth of gears, comprising, in combination, a standard, a knee adjustably connected thereto, cutter means mounted on said .standard for forming teeth on a gear blank, 2. gear member on said standard, an indexing gear for said blank adapted to mesh with said member, a

' support for said blank and gear movable on said knee, cam means on said knee for reciprocating said support, driving means on said standard, and transmission means including-a flexible shaft between said driving means and cam for rotating the latter when said knee is in different positions of adjustment.

22. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to rotate said cutter means, a support for said blank, and cam means for feeding said support relatively to said cutter means at a varying speed in the course of a tooth cutting operation. v

23. A machine for cutting teeth of gears comprising, in combination, cutter means for forming teeth on a gear blank, means to to tate said cutter means, a support for said blank, and means for automatically feeding said sup-port relatively to said cutter means at a speed which varies progressively according to the varying work on the cutter means while forming a tooth.

24:. In a gear cutting machine, in combination, a rotary cutter provided with laterally projecting teeth for cutting curved teeth on a gear blank, means to rotate said cutter, a support for holding the gear blank in position to be acted upon by the cutter, and cam means for feeding said support relatively to said cutter at a varying speed in the course of a tooth cutting operation.

25. In a gear cutting machine, in combination a rotary cutter provided with laterally projecting teeth for cutting curved teeth on a gear blank, means to rotate said cutter, a support for holding the gear blank'in position to be acted upon by the cutter, cam means for feeding said support relatively to said cutter at a speed which varies in accordance with the varying Work on the cutter while forming a tooth, and means for imparting a rotary motion to the blank during the cutting operation.

In testimony whereof I have signed my name to this specification.

WILLIAM c, FARN. 

